Does masturbation have to lead to orgasm?

Not Always. Sexual stimulation, whether with a partner or alone, does not always result in an orgasm. Masturbation allows you to find the right combination of pressure and tempo to result in an orgasm or multiples. This information becomes helpful when you and a sexual partner are learning how best to stimulate you to orgasm.
No. You can stop before orgasm. Sometimes orgasmic state can not be reached.